1. Field of the Invention
The present invention relates to reclosable plastic bags having slide zippers. More particularly, the present invention relates to a method and apparatus for making slide-zippered reclosable bags on form-fill-seal (FFS) machines.
2. Description of the Prior Art
Methods and apparatus for manufacturing reclosable plastic bags on FFS machines using reclosable zippers are well-known in the art. These prior art methods and apparatus, however, are limited to interlocking zippers which are directly opened and closed by the hands of the bag user and are not designed for the utilization of a slider for opening and closing the zipper.
The method and apparatus of the present invention, on the other hand, relate specifically to reclosable bags having a slide zipper. Reclosable bags having slide zippers are generally more desirable to consumers than bags which have traditional interlocking zippers since it is much easier for the user to open and close bags having a slide zipper. It is thus commercially highly desirable and advantageous to provide a method of and apparatus for manufacturing slide-zippered reclosable plastic bags in a continuous, automated process.
Slide zippers for use with plastic bags are well known in the reclosable fastener art. Examples of conventional slide zippers can be found in U.S. Pat. Nos. 5,007,143, 5,008,971, 5,131,121 and 5,664,299. Typical slide zippers comprise a plastic zipper having two interlocking profiles and a slider for opening and closing the zipper. The slider straddles the zipper and has a separator at one end which is inserted between the profiles in order to force them apart, that is, the separator plows between the profiles forcing them to disengage. The other end of the slider is sufficiently narrow to be able to close the zipper.
Recently, a new type of slider zipper has been developed which, as discussed fully below, improves on prior art slide zippers and includes features which facilitate the manufacture of bags in automated form fill processes.
It is therefore the object of the present invention to provide a unique and novel method and apparatus for making slide-zippered bags on an FFS machine.
The present invention is, in two aspects, a method of making slide-zippered plastic bags on an FFS machine and an apparatus for making slide-zippered plastic bags on an FFS machine.
In a first embodiment of the present invention, the slider is preapplied to the zipper at the zipper manufacturing site. Then, at the FFS site the plastic bags are made on the FFS machine utilizing conventional and well-known FFS technology, such as disclosed in U.S. Pat. No. 4,894,975. To facilitate guiding and alignment of the zipper, the zipper is provided with guiding flanges.
In a second embodiment of the present invention, the plastic bags are made on the FFS machine and the zipper is attached to the bags in the conventional manner. A coil of sliders, each slider being connected to its two adjacent sliders, is used to feed the sliders into the FFS machine, which sliders are then applied by a slider insertor mechanism to the zipper. In a slight variation of this embodiment, the slider insertor mechanism can be positioned to apply the sliders to the zipper before the zipper is fed into the FFS machine for sealing to the plastic bags.
In a third embodiment of the present invention, the plastic bags are made on the FFS machine and the zipper is attached to the bags in the conventional manner. A magazine of individual or interconnected sliders is used to feed a slider insertor mechanism which applies the sliders to the zipper. In a slight variation of this embodiment, the slider insertor mechanism can be positioned to apply the sliders to the zipper before the zipper is fed into the FFS machine for sealing to the plastic bags.
In a fourth embodiment of the present invention, the plastic bags are made on the FFS machine and the zipper is attached to the bags in the conventional manner. Bulk sliders are introduced into a vibratory feeding bowl which orients and feeds the sliders to the slider insertor mechanism which applies the sliders to the zipper. In a slight variation of this embodiment, the slider insertor mechanism can be positioned to apply the sliders to the zipper before the zipper is fed into the FFS machine for sealing to the plastic bags.
The present invention will now be described in more complete detail with reference being made to the figures identified below wherein the same numerals represent identical elements.